Receiver for wireless telegraphy and telephony.



G. W. PICKARD.

RECEIVER FOR WIRELESS TELEGRAPHY AND TELEPHONY.

APPLICATION FILED MAR.9.1910.

Paen'odune 6, 1916 Mara? (gru i vu EENLEF VHITTXEB PIQKRD, OF AMESBURY,MASSACHUSETTS, ASSG' a- EFE@ WRELESS SPECILTY PIPABATUS COMPANY, 0F NEWYORK, N. Y.. CQ-,

TIQN QF NEW YORK To all 'ze/5,0m t may concern.'

it lreoivn' that I, GRuENLri/ir TW. Piou- Aiui, a citizen'of the UnitedStates of einer ica, and a resident of Amesbury, Massachusette, haveinvented certain iieiY and useful liiiproveuients in Receivers forllfireless Te# f legraphy and Telephony, the principles of ivliicl. areset forth in the following speci iication and accompanying drawings,which disclose the form of the inventionwhicli now consider to be thebest of the various forms in .which the principles of the invention maybe embodied. Y

This inventioii relates to ineens, for re" tric Waves.

"lie object oi the invention is to provide commercially useful means fortranslating i the energy of minute high frecuency oscillations oralternating electric currents'iiito a forni capable of efficientlyactuating an indieating mechanism.

lliave previously shown (l`he measuremerit o'received energyet'ryireless stations, Elecri'cal Review, December ith, i906; Solidrectiiiers, Electric@ Ire/view, Februery 20th, 1999) that theminuteoscilletcry currents in the receiving circuits of a wire-- lesstelegraph or telephone station are' of sufiicient energy to directlyactuate a sensitive y indicating mechanism, such as a telephonereceiver, if only this energy be converted into a "form (i. e., directcurrent) suitable for operating-the indicating mechanism. The

truth of tnis statement has been amply demonstrated bythe successfulcommercial use.

ci several forms of my detector, the solid rectifier detector, in which,by means of rectication,tlie received oscillations are con verted into adirect current form capable oi y operating the indicating mechanism. i y

in my improved forni of receiving circuit, rectification is no longerused as a means of transformation, the received oscillations lieiugconverted into direct curi-ent by means ci an abrupt change in thecharacter or con stents of the receiving circuit during the receipt ofoscillations.

- 0f the accompanying drawiiigs,'i4`igiire l; 'is a diagrammaticillustration of a Wireless telegraphy or telephony receiviiigl stationin which the invention is embodied. 2 "is a modied form of theinvestiert Secicatien of Letters Patent.

ceiviiig iritelligeucev communicated by elec-v Ainductan'ce L, this stln Fig. l the aerial conductor, or antenna, A, is connected to earth,Gr, through an inductaiice L, which should'be 'variable to permit oftuningn In shunt around this inductaxiceL is connected the indicatingmechanism or signabproducing device such. as a inductaiice li aridtelephone R are sliuuted intermittently and abruptly by the vibrator.'in operation, Fig. 1, the passing trains of electric Waves set upelectric current oscillations iii the tuned circuit A, L, G. Thiscircuit, containing' both inductance and capacity, is a resonantcircuit, 'and the energy therein .alternates i'roiri the static to thekinetic form, being' alternately inthe shape of an electrostatic fieldaround the antenna A, and oil a magnetic field iii and around theinductaiice L.. At definite intervalathere 'ore,"the received energy isstored in the magnetic eld or' the inductance L. lf at such time thetelephone receiver R is abruptly connected, cy the operation of T,around the Jd energy is prevented from swinging bach of the circuit,(such as the capacity of the wire oil antenna A), but. instead, as themagnetic ifield collapses, is ydischarggjed through the telephonereceiver, bausing the .produc tion ci' a cliclr or sound.l The rate atwhich a given discharge taires place is, of course, entirely governed bythe resistance and iiiductance of the telephone receiver R, and theinductance L, and not et all by the 'requericy of the oscillations iuthe resonant circuit which produce the lield about L. rllie discharge istherefore such as to effectively operate the telephone receiver R. Theacn `tion of 'T is in :eect to 'cut out. the induc- .teiice L from'tlie'resoiiant-eircuit in lwhich the oscillatious Were-produced, andpreferably at e time rilieii lilies the maximum" Patented Furie d, luid.l Application cd .'xzarci 9, 1910. Serial No. 548,130.

to the capacity element amount of energy about it in the forxnof itsmagnetic iield; and the claims hereof are intended to include just thisaction, to the end' oit discharging the energy through R. The eect ofconnecting R in shunt to L is to cause the energy of the field toproduce a pulse of cent which passes through B. This is a direct currentpulse and therefore highly eiicient in operatingthe telephone receiver.The compulsion of the current through the telephone circuit permanentlyremoves this energy from the resonant circuit, but the inductance L isconnected in 'the l resonant circuit ready to be again charged by thecsciilations of energy therein newly received from additional etherWaves. in brief, starting with an inductance coil in a suitable or knownoscillation circuit, the invention includes such combination therewithof an interrupter (i. e., intermittentlyactiug device) and adirect-current signal-producing instrument such as a telephone and oflow resistance, as will cause the operation of the signal-producerby thepulse of current caused by the collapse of the magnetic tioid about theinductance. This i. a coniplished by the action of the interrupter inconnecting together the inductance andA signal-producer at a time whenthe energy yet exists in kinetic form in the iield the inductance, andbefore` such enn has reverted to the static form iu the capacity elementof the oscillation cil-cuit so that the current pulse produced by there* suitiug ccilapse ot' the field conveys the energy which was storedin the field over to the low resistance and therefore eliicientsignal-producer instead of permitting' such energy to revert to thevstatic form in the capacity element of the oscillation circuit.

'1W hile the invention is operative with spark sending, it is not sowell adapted for that as for undainped wave sending, on ac count of thedi'liculty in shunting L by at iicient strength of field about L to theeiieient amount ci' ennipir-.g oscillations Wave iovvever, undarnpedWaves are ig, all that is necessary is that operated during the receiptof a 'wav as `in Wireless telegraphy, or a continuous train of varyingWaves as i' t.. eiess telephony, Witiout especial nce to the rate of Trelative to the x p. `ivave-train or trains. Jalso the energy .field otL is eliciently tapped into at co'nparativeiy lov! rates of vibra 'i n"it", because action not only occursivhen El actualy makes contact, butcontinues through the minute spark across the o 'i when they areseparated-by a c distance oL a fraction of a micron. The operation of Tfor telegraphic use at a rate oniy a ien' times greater than theoperation possesses the great advanta of the sending key produces verygood ren Lieavir sults in telephone Qd, and even i of the invention,Withoutany vibrator at ali,

butsiniply by the manual operation of a key in the place of T. 0fcourse, the use of the invention does not cause the diversion of all theenergy of the field ot lli to R, be cause a large amount of it is shutoil frei-u R when the contacts of if are wide apart; but the action isvery edi/cient as compared with the best detectors, and the invention geover use under s.,

.,rwhen of detectors in that.I and interference.. i vibratory maireuoperated in any ay ing niake-and-breair devices.

Vhen it is not desired or is inconvenient to employ the auxiliaryenergy, required to operate T when it consists oit a vibratingn1ake-and-break device, T consists of a device having no parts requiredto be moved, such as a finely-adjustable minute sparkgap, or amicrophonic contact. Any such f device may be used in the circuit ofeither Fig. l or Fig. 2, being operated by the rise of potential acrossits terminals to cause the effective shunting of R around L. li? ainicrophonic conta-ct be used, instead ofi the sparlrgap, then apreferable form is. one of the various welldrnown selt-restoririgj deWvices, so that the telephone it is automatically cle-shunted frominductance L, the device then being, like the vibrator or minutespark-gap, an' intermittently-acting device.

The device T may be used with any form of antenna, including my magneticloop an tenna of Letters Patent No. 876,996. ln that specific case theinductance of the ioop itself acts as the inductance L hereof. 'infactin any case the inductance need not be in the fornil of a Winding,although that form will generally be preferred. v

The ordinary present-day telephone receiver is believed to be at thepresent time the best device for use at R. But it should be of lowresistance, and the one E have successfully in the invention had a resitance of only one ohm.

As above suggested, this invention possesses the great advantage thatthe device T,

The modified circuit shown in Fig. 2 opv crates in almost exactly themanner s that of Fig'. l. Here, however, the receiver B; is normally apart et the sci tion circuit fa, L, R, Gr, out ciosure ci? T throws theinductance L, the telephone r eceiver R, and T in series, justas withthe circuit shown in Fig. l, and the discharge of the inductance takesplace in the. same inanner, and WithA the same resultfif'. e.,'a clickor sound from the telephone receiver. Thus "llo far in my use of theinvention, this modifilcation of Fig. 2 produces better results thanthat of Fig. 1.

I claim:

l. The method of receiving intelligence by electric waves, whichconsists in storing the energy of the Ware-generated oscillations aroundan inductance in the form of a magnetic field. and then discharging saidstored energy in the form of a pulse of current, through asignal-producing device, by abruptly closing a circuit including saiddevice and inductance.

2. The. method of receiving intelligence transmitted by electric waves,which consists in intermittently causing. first, the establishment ot' amagnetic field about an ingluctancc by the passage ot' oscillatingcurrents generated by said waves, and second, the passage through adirect current signal producing instrument, ot' a pulse of directcurrent generated vby the collapse of said magnetic field.

3. Means for receiving intelligence communicated hy electric waves,which consists of an inductance; a direct current signal producinginstrument; and means for intermittently causing, first, theestablishment of a magnetic field about the inductance by the passage ofoscillating currents generated by said waves, and second, the passagethrough said signal-producing instrument, of a pulse of direct currentgenerated by the collapse of the magnetic field about said inductance.l'

Je. Means for receiving intelligence communicated by electric waves,which consists of an inductance; a direct current signal producinginstrument, included in an oscillating current circuit in series withsaid inductance; and means for intermittently causing, first, theestablishment of a magnetic field about the inductance by the passage ofoscillating currents generated by Said waves, and second, the passagethrough said Vsignal-preducing instrument, of a pulse of direct currentgeneratedby the collapse of the magnetic field about said inductance.

5. Electric wave receiving apparatus which comprises an inductance, atelephone receirer, and an interrupter, connected in series with eachother, the interrupter being arranged to intermittently connect thetelephone receiver in circuit with the inductance and thereby operatethe telephone receiver by the pulse of current from the collapse of thefield about the inductance.

1'. Elect-ric wave receiving apparatus which comprises an inductance anda telephone receirer connected in `series with each other in anoscillating circuit, and an interrupter connected around them both andarranged to eii'ectively connect the telephone receiver in shunt to theinductance and thereby operate the telephone receiver bythe pulse of thecurrent from the `collapse of the field about the inductance.v

7; Electric wave receiving apparatus, which comprises an inductance, alow resistance direet-current signal-producing instrument, and aninterrupter acting to shunt through the signal-producing instrument thepulse of current produced by the collapse'of the magnetic field aboutthe inductance.

8. Electric wave receiving apparatus, which comprises an inductancedevice in a circuit including capacity, a signal-producing device, andmeans for intermittently disconnecting the signal-producing device Jfromthe inductance and connecting it therewith when energy exists in amagnetic field about the inductance.

9. Means for receiving intelligence comvmunicated by electric waves,which consists of an inductance coil and a signal-producing instrumentboth permanently connected together in a circuit in which oscillationsare setup by the signaling waves; and means for intermittently closing acircuit other than said ose-llatinvl circuit but which also containssaid coil and instrument.

GREENLEAF WHITTIER PICKARD.

Witnesses:

EDWARD H. RowELL, MYRA S. ROWELL.

